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definition and notation

...
y> and <
y,
x> are in general not identical). Let
x and
y be any classes, as (for example) those of the dots on the two arms of a stippled cross. The
intersection of
x and
y, symbolized as
x ∩
y, is the class the members of which are the objects common to
x and
y—in this case the dots within the...

The
intersection operation is denoted by the symbol ∩. The set
A ∩
B—read “
AintersectionB” or “the
intersection of
A and
B”—is defined as the set composed of all elements that belong to both
A and
B. Thus, the
intersection of the two committees in the foregoing example is the set consisting of...